In Hour 4, we talked about using crease edges with polygonal geometry as a way to preserve sharp edges in your model when you smooth it. Find this tool under Edit Mesh, Crease Edges Tool. Crease edges only update interactively with Mental Ray’s smooth mesh preview. If you want to take advantage of crease edges, know that they will not update interactively when you use the Mesh, Smooth command. If you make adjustments to the creases, you must delete the polySmooth node or delete history on the model and apply the Smooth again.